Brake mechanism



Nov. 7, 1944. J. H. PETERSON BRAKE MECHAN'I SM Filed March 29, 1943 Patented Nov. 7, 1.944

UNITED STA-TES PATENT OFFICE BRAKE MECHANISM JohnA H.Peterson, Silver Gity, Iowa.A Application March 29, 1943,.sa1 No. 480,920' 2 claims. 01. isa-78) This invention relates to brake mechanisms more particularly for. automobiles, trucks and the like.

It is an object of the invention to provide a hydraulically' actuatedbraking mechanism so constructed and assembled that an increased and more eiiicient braking surface is provided.

Another object of the invention is to provide a brake mechanism for the' above stated purposes Which may beperfectly and easily adjusted for compensating for the" wear on the brake lining strip thereof and also complemental to the thickness of linings. Y

A still further object of the invention is to provide a braking mechanism which is so constructed and assembled that in operation the entire area of: the surface of a brake lining is employed for applying a braking .force to the brake drum of a vehicle. An important objectl of the invention is to provide a brake mechanism so constructed and arrangedl that the impetus of the travelling movement of avehicle is utilized for actuating said mechanism for decreasing said impetus during a decrease in the speed of said travelling movement of the vehicle".

Other and` further objects and advantages of the invention will be'underst'ood from the following` detailed description thereof.

In the drawing abrake shoe employed and shovving an aperture of preferred special shape.

As heretofore practiced in the art, numerous braking mechanisms for automobiles and the like have rbeen vemployed which, include ra pair of: oppositelydisposed brake shoes, the latter having Vends which are directly, pivotally secured to a support,l the other ends thereofbeing arranged to movezaway from each other at times when aforce iszapplied to said other ends and.

Withthe resultthat ,portionsof said shoes vadjacent said'other ends only engagera brake drum, said pivotally secured ends ofhsaid prior constructions not providing braking functions, since saidy endsdonotmove against their ,adjacent brake drum ange, andthe present invention' aimsto obviate the undesirable features of the prior practice by providing afconstruction which utilizes all of the area of a brake lining surface simultaneously for-a comparative' increasexof the braking' force vapplied toa brake drum. Referring now tothe drawing for a more par-- tic'ular description, 10' indicates generally a brake/drum having a plate H which is' circular in plan anda perimetrically disposed flange I2. Thel plateYV II- is# axially and vertically secured toaV vehicle' Wheel inawell knownmanner, not shown-",Whereby'at times when the wheel revolves the brake drum is provided with correspondinglyrevoluble movements.

Figure 1 is a side elevation of a brake'mecha- A Figure 3 is a plan view" ofV a brake shoe adjusting mechanism employed, certain portions thereof being broken away and others showing in* section.

Figure 4 is a side vieW'of an eccentrically disposed bushing' and an integral' shaft therefor.

Figures 5v and 6 are, respectively, views* of opposite endsv of the device shown in Figure 4'.

Figure 7 is a sideelevation of a shaftlslee've having an integral second' eccentrically disposed bushing thereon; l Figure 8 is` an endI view of the sleevefsliaft shown 'nFigure'T.

Figure 9- is a side elevation of' a connecting rod employed.

Figure 10` is a view ofthefother end of. the eccentrically disposed bushing. shown in Figure' '7. Figure 11' is a' side elevation of a fiagment'of A cover orbafaking-plateA I3 is provided for the druin I'U, said plate i3 beingl secured to and sta-- tionary'r with' respect-- to the rear axle housing of an automobile in a-'well known manner by cond ventional means which^may include cap screws disposed through the apertures M- of the plate i3'.`V The' platevv Lipreferably includes afflange I5*Which'is 'snugly disposedabout"l the ange- |12 of the brake' drunr for providing an enclosed gated Wall 2l and an approximately vertically disposedwall 22, and it will be understood that the diameter of the shanks of the cap screws I5 is less with respect `-to either elongation of the apertures I8, for purposes later described.

The Shanks I9 of the cap screws are threadedly Y u secured to the stationary backing-plate I3 and a spacing block 23 is disposed about each shank between the backing-plate I3 and the shoes I6, and I1 for holding the latter a selected dis- VIIS thereof. The nut 39 bears against the exterior surface of the stationary backing-plate I3, as shown in Figure 2. As thus described, it will be noted that an operator may apply a wrench to the angular end portion 38 of the shaft-sleeve at times when the nut 39 is loose for rotating the shaft-sleeve by means of said wrench for the purpose of disposing the eccentric bushing 31 in a selected position and for moving the connecting rod- 26, togetherwith theshoe I6 and the brake lining `strip thereof,towardor away from the annular-flange I2 of the brake drum ,I0 and to a distance complemental to the thickof the shoe I5 at said time sliding with respect to the upper cap screw I9, the latter being secured tance from said plates of the 'drum I9. The horizontal walls 2l of the apertures I8 normallyV` rest upon the Shanks of the cap screws I9 so that the shoes IS and I1 are also supported upon the shanks of the cap screws.I AThey shoes are freelyV slightly slidable in horizontal directions as well as slightly movable in vertical' directions and against the urge oflater described springs, since as above stated, the diameter o'f the Shanks of the c ap screws I9 is less than the width of either of the elongations of `each aperture I8.

` Each shoe I6 and I1 is provided with an arcuate flange or segmentalportion 24 to which strips of conventional brake lining 25 are secured by a suitable means, not shown, such as rivets or the like.

Two connecting rods 291and 3I are employed for the upper and oppositely disposed spaced to the stationary backing plate I3.

Referring to Figures 4, 5 and 6, the shaft 40 is provided at one of its ends with a threaded apart vends of the segmental shoes I6 and I1. As

shown in Figure 9, the connecting rod 26 is provided with an eye 21 at oney end, the other end thereof being bifurcated and provided with oppositely disposed ears 23 and 25, the latter being best shown in Figure.l 3. Aligned elongated apertures 35 are oppositely `disposed through the ears 28 and 29. The connecting rod 3| is of like construction, except that it is provided With an offset portion 32 so that the ears of said rods are disposed in alignment with respect to each other for tting about the inner edges of the shoes I6 and I1. Connecting pivot pins 33l are disposed through vand secured to said shoes. Opposite ends of the pins 33 extend through the elongated apertures 35 of the .rods rfor pivotally attaching the rods to said shoes, said attachment 4being loose to the extent of the elongation of the apertures 30, for the purposes later described.

The eyes 21 of the rods 26 and 3I each iit snugly about and pivotally with respect to eccentrically disposed bushings, the latter being formed integral with their respective shafts, and for compactness of assembly one 'shaft extends through the other.

Referring to Figure 7, a shaft-sleeve 34 is provided at oneend with a threaded portion 35 and an angular end portion 36 for receiving a wrench for purposes later described. The other end of the shaft-sleeve 34 is provided with a bushing 31 which is eccentricallydisposed with respect to said shaft-sleeve, said eccentric bushing being disposed through the eye 21 'of the connesting rod 26, as shown in Figure 3. .Y rlhe shaft'- sleeve 34 is provided with an "annular step cut as at 38, said annular step, as best shown in Figures 2 and 3, being disposed against the inner surface of thebacking-plate I3 and a nut 39 is provided uponthe threaded Portion 35 portion 4I and a slot 42 at the outer end thereof for receiving a screw driverfbit. The shaft 49 extends through the hollow shaft-sleeve 34 and the inner end of the shaft 40 is provided with an integral eccentrically disposed bushing 43 which is received into the eye 21 yof the offset connecting rod 3 i, as shown in Figure 3.

A Washer 44 is disposed uponv the outer end of theeccentric 43 'and maintained during use by means of a Cotter pin or similarv suitable keeper 45, said keeper extending through an aperture 46 of the eccentric bushing 43,' as shown in Figure 1.

A spring 41 is connected to and between the upper ends ofthe shoes I6 and' I1 for normally urging said shoes toward each other. A nut 48 is disposed upon the threaded portion 4I of the shaft l4S), and at times `when said nut is not' posed bushings, the latter pushtheir respective connecting rods,fpins' 33, and shoes toward the flange I2 against the urge of'thespring 41. The

elongated apertures 30 of the connecting rods 26 and 3| are provided forvpurposes later described.-

the lower ends' of the shoesIB and I1 for normally urging said ends toward eachother.' Y

u The upper end of the piston ro'd 53. extends into a piston cylinder 55 and is provided withv a piston head 56. l Within the cylinder and between the upper end thereof and the piston head 58, hydraulicbrake uid is disposed, and the latteralso fills aconduit 51.' p The conduit 51 extends'vthrough the stationary backing-:plate I3 Aadjacent the upper portion l aaeasoai.

. thereof, and isin' communicationY with the brake pedal of theY vehicle iny a'well known` manner, whereby. at times when said pedal is depressed pressure is transferred through said brake fluid contained in thev brakingsystem of the vehicle and the conduit l and applied to the-upper end of! the piston head- 58 for causing a downwardv movement of the piston rod 53, thereby causing-I the outer ends of the links 49 and 58- to spread apar-t against the-urge of the spring 54.

The piston cylinder 55 is provided with oppositelyv disposed` ears 58, 'the latter being riveted or-A otherwise suitably secured to the' stationary ment of saidv shoes away from eachother and' against said ilange is necessary for applying a braking force to the revoluble flange I2.

The shanks of the cap screws being slightly less in diameter .than the width', at any point; of either ofthe elongatons of any of the apertures I8, said Shanks at times when the shoes are in a normal position, as shown in Figure l, are then disposed' closely adjacent the junction of thewalls 2| and 22' of the apertures I8, whereby at the time the shoe I6 moves upwardly, as later, described, the

elongated walls 22. of the apertures I8 of the.v

shoe I6 slide upon thek Shanks of the ca-pscrews I'9jof1the shoe IB for permittingv aslight upward, vmovement ofthe shoe IS. At times when the shoe |81 isV moved. outwardly, as later described, the wallsv 2| of the apertures I8 vofthe shoe .I6 rest upon andsliolably engage the Shanks of the cap screws I9 of the shoe I6'. It will beunderstood that said sliding movement is appreoiably minute and neednot bein excess of one sixty-fourth of an.,inch`,and especially at times when the brake liningof the shoe Iis not unduly worn. It will also be understood that at .times when. the take-up adjustment mechanism, which includes the eccentricbushings, is employed for compensating for wear of the brake lining V of the shoe I8,

whereby the outer edge of said brake lining isI disposed closely adjacent to the inner wall of the ilange I2 ofl thebrake. drum, said slidingmovement neednot be greater than one one-hundredth of: an inch, or less.

ThewallsZI of the apertures I8 of each of the Ashoes I6` and I'I are approximately horizontally` disposed and carry the weight of the brake shoes thereon at times when said shoes arein a normali is applied to either the front orrear wheel of' theA vehicle andat the left-hand side ofthe driver: or operator; the flange I2. of the brake drum II is then revolving in the direction of the arrow |00.

To set the brake, the operator depresses theI brake pedal ofthe vehicle and but slight pressure need be applied by his foot upon said pedal, whereupon the outer ends of the toggle links 49 and 5I) spread apart and cause a corresponding movement to be applied to the lower ends of the shoes I6 and I'I.

YThe motion of thetoggle link 49 caused by a downward movement of the piston rod 53 urges the lower end of the brake shoe .I6 toward and against the flange I2, and upon the lower end of the brake lining 25 of the shoe I6 engaging said ilange, the revoluble movement of the ilange I2,

I6 andv its lining 25E to. become moved'` upwardly; similarly. to: a. personr placing his'hand upon a: re` volving pulley,l whichcauses hist handtobe movedi slightly in the. direction -the pulley is rotatingrf.

The contact of the lower end of the lining: 25.of\ theshoe |61 with the flange |2.causes1 the shoe I6 to. be moved upwardly and vin the direction;` ofi ros. tation of: the. flange4 |22.. Suchl upward: movement. iszvery slightiandis permitted on accountofthe. elongationzof the apertures I8: ofv theshoe' I6, whichlinclu'de 'the walls: 22? of saidapertures.k y

Itwill be noted; that` the .upper end 'of the shoe I6, when forced: upwardly as abovevdescribedglwilll also4 swing:` outwardly and. toward. the4 flange.l I2=,.. since the connecting=rod126`forces the upperend' of. the shoe outwardly, duringan. upward move? ment' of the'slioawhereby.I the entire area of. thei outer side.. ofthe brake lining 25: engages the flange I2'. n Y w yAt the time thebrake,shoe` IBL moves upwardly` and inthe. directinaofthe arrow |00, the pin 33'? of-"the shoe I6 is then disposed at that end ofthe aperture 30 whichis. closest to the eye 21 of.' the rod 26,' said upward and outward movement of thesho'e I6 beingag'ainst the urge'of the spring- 4l, the latter holding the shoe I8 andits liningV away 'from the flange I2 at times when the shoe`r I6 is in a normal position, as shown in Figure v1.

-The flange I2 being revolved in the direction of the'arrow |00, then causes a downward movementor the other shoe |"I, since the lower end.

of the lining 25 of the shoe I'I is then engagedl with the flange vI2, said" downward movement being infinltesimally slight, and since the lining 25 ofthe shoe I'I isthen engaged with the flangev I2th`e upper end of the shoe II swings outwardly" and slightly downwardly against rthe urgefof the spring 41, said outward movement being permitted since the aperture 30 of the connecting rod 3| is elongated and since the diameter of the Shanks' of. thebolts I9 is slightly less than the width of the horizontally disposed portions of the apertures.

r I8. At this time the shanks of the bolts I8 of the shoe I'I are in approximately the position withV respect to the apertures I8 ofA the shoe I'I as shown inFigure 11. Thelining 25 of, the shoe `I'I,v being'swung outwardly as described, said. lining. then.-bec0mesv engaged with. the flange I2 as to. all portions of the outer surface of said lining. for. causing both brake shoes to become set-practically instantaneously and simultaneously atthe timethe operator depresses the brakepedal very slightly as compared to the prior practice.

Assuming that thevehicle is travelling rearwardly andrthat` the brake drum I I is rotating in adirjection that is reverse with respect to the ar' row |00, that the vbrake shoesare in the normal position shown in'Figure 1, and that a slight pressureis applied yto the linksyof the toggle joint.A through the pistony rod 53, a reverse cycle of events;r

isithereby-occasioned;. that is, the brake shoe I1` moves' upwardly and.` outwardly andthe brake;

shoe I6 moves slightly downwardly and outward'- ly for setting the brake shoes against the flange I'2, and without a positive locking of the shoes` long as the pressure is suflicient to'cause the lower ends of the brake shoes to touch the flange I2,

inrithedirectionsof the". arrow |40, causes theshoe;A

during` travel of. the 'vehicle' i'n- :either fdirection',`: therevoluble motion yof the'flange: I2 completes? a-setting of the brakev shoesandwithout further pressure oilv the operators foot, as vhasbeen neces-I sarywith the* hydraulic zbrakingr mechanisms-ory thepriorfart. It willsalso benoted thatI yprovide abra'kef mechanism having parts so 'constructed andar-e4 rangedI that the velocityoi. the vehicleis utilized. fordecreasing the speed. of travelling movement of the 1vehicle iny either direction, andwith avery slight. pressure on the brake pedal ,of the-vehicle.V :rA't the time theoperators fo'otis removedfrom the, brake pedal, the spring 54VV draws the lower ends of the shoes I6 and/.I1 toward each other, moving the inner ends of the links 49, and 50 ,upwardly, together with thepiston rod 53, the lower bolts' I9v being then in position `witlrrespect ,tot the lower apertures I8 of the'shoes adjacent the junction of the walls 2| and 22 of said apertures and the upper spring 41 draws' the upper ends of the shoes I6 and I1 towards each-other, the elongations'of the apertures 30 of the connecting rodsv 26 and 3l permitting `the same. Y

actual practice the length of the elongations of the apertures I8 is comparatively muchless thanl as shown in the drawing, vsaid elongations being depicted long in Figure l to facilitate an illustration and explanation. L

. As shown in Figures l and ,3, for convenience of illustration, theeccentric bushings 31 and43 are ydisposed in their extreme position of adjustment whereby a `further adjustment of the upper eindsnof the shoes I6 and- I1 toward the flange I2 is not possible, and it will be noted that the lower` endslof said shoes are selffadjustable with respect to .wear on their respective brake lining strips ,25.

:The eyes 21. of the rods 26 and 3l are pivotally mounted on their respective eccentrically dis,-I posed 'bushings However,4 said bushing pivotal connection of said eyes and rods is also eccentrically' disposed with respect to the axisof the rotatableannular liange" I2 as is essential, saidbushings each being disposed approximately twotvhirdsof the distance of the flange I2 lfromvthe` lattrs axis, said rods being of suicient length' to' causethat end of the shoe I 6 to beforced outwardto which the rod 26 is attached at'the tmerthe lower end of the shoe I6 engages `the flange I2 when the latter is moving in the direction'of the arrow |00. The other rod 3Iis alsol ofsufi'cient length in conjunction Withjtheelongation of its aperture'30 to permit the end of the shoe I1 to which it isattached to swing orgslide downwardlyagainst the flange I2 at the Vtime thev lower end of -the shoe-|1 engagesl the flange `I2 while the latter is revolving in the direction of the arrow IUI), whereby the juxtaposed shoes I6 and' I1 both apply a braking force simultaneously to the :flange I2, :said shoes sliding `orswin'g'ing slightly, for said purpose, the substantially. L.1 shaped' apertures I8 permitting said sliding Vor swinging at the time thehydraulically actuated pressure` means isv applied to, the toggle-.links -by the operators footl and rbrake pedal ofthe vehicle. 4 A1 aaeggeoe,

f Said apertures I8 also permit the means which is'responsive to engagement of the lower juxta- I posed ends of the brake shoes with the revolving ange I2 to operate for causing the upper juxtaposed ends ofthe brake shoes to also engage the sure is removed from the toggle links 49 and 50.

From the foregoing description it is thought to be obvious-that a brake mechanism constructed in accordance with my'invention is particularly Well adapted for use by reason of the convenience and facility with which it may be assembled and operated, and it will also be obvious that my inventionis susceptible of some change and modication without departing from the principles and spirit thereof and for this reason I do not wish to b e understood as limiting myself to the precise arrangement and formation of the several parts herein shown in carrying out my invention in practice, except as claimed.

I claim:

1. In a braking mechanism, a revoluble brakedrum `having'an annular iiange, a stationary backing-plate for said drum, the normal operating positions of said plate and flange being vertical and horizontal respectively, a pair of brake-shoes juxtaposed within the plane of said flange, each shoe being provided with a plurality of spaced apart apertures of substantially L-shape in plan, one of the arms of each aperture being disposed substantially vertically and the other arm of each aperture being substantially horizontally disposed, bolt Shanks or lesser diameter than the width of the arms of said apertures disposed through the latter, ends of said Shanks; being secured to said plate at one side of said shoes, heads of said bolts being disposed at the other side of said shoes for loosely holding said shoes slidably adjacent the inner surface of said plate, and springs connected to and between the juxtaposed ends of both of said shoes for urging the latter toward each other.

2. A braking mechanism for a vehicle wheel or the like having a brake-drum provided with an annular nange, a backing plate for said drum secured to a stationary portion of said vehicle, a pair of brake shoes juxtaposed with the plane of said flange, each oi said shoes being provided with a plurality of spaced apart apertures having vertical and horizontal arms, fastening means having shanks of lesser diameter than the width of the arms of said apertures disposed through the latter, said shoes being loosely carried by said plate to dispose their outer surfaces respectively adjacent to the inner annular surface Vof 

